11, Number 8
A Gossman Consulting, Inc.
In 1980, at the
commercial hazardous waste fuel facility at a cement plant, there were
initial specifications for heat content, nitrogen, chlorine and
sulfur. Early attempts to develop methods for these
met with mixed success. Heat content was performed using an automated
adiabatic Parr bomb colorimeter – model 1261 to be exact.
were derived from ASTM Standards for coal but were modified to handle
the volatile liquid waste fuels. Early attempts to use
capsules supplied by Parr and mylar film covers to avoid evaporative
losses were quickly abandoned. The method adapted was to
the sample and quickly withdraw a 0.5 – 1.0 g quantity into
cup, covering that with a second inverted cup for weighing, and then as
quickly as possible placing it into a prepared oxygen bomb. This basic
method is still being used 26 years later. Better automation has
simplified the bomb prep and computers now calculate the equilibration
point, cutting the time for this determination in half.
is part of a
series of GCI Tech Notes focusing on the early
development of the hazardous waste fuels programs during the early
1980s. I was hired as the facility manager for the first
hazardous waste operation at a cement plant in early 1980.
developments in storage, processing, testing and use of hazardous waste
fuels were the result of work done at a handful of plants in the early
and mid 80’s. Look for issues to include topics on
testing methods, processing and the impact of HWF on cement product
quality and production.
Content, Ash, Halogens and Sulfur Test Methods in HWF – The
David Gossman, Gossman Consulting, Inc.
In 1980 there were methods for chlorine and sulfur in coal using
analysis of the wash from the bomb. These were time consuming wet lab
techniques. For example, sulfur required precipitation, filtering, and
drying the filter in an oven. A Hach turbidometer method
from sulfate determinations in water was used with success for some
time. Hach methods for chlorine and chloride did not work
the bomb wash. Attempts to use a chloride ion probe met with similar
failure. Eventually a silver nitrate titration with a
endpoint determination was adapted. Many facilities today use a
variation of this method where a chloride ion probe is used for the
Nitrogen was an altogether different story. Early attempts to use a
Hach kit for nitrate identified a significant background level of
nitrate in the bomb wash that varied depending on the heat content and
amount of sample being combusted. Correction curves were developed and
used for some time but QC issues continued to be a problem.
The only procedure for ash was the traditional ceramic cup in a muffle
furnace. There was a tendency to get significant sample loss
the volatiles boiled off the sample and it was time consuming
– but it
worked. Over the course of that first year we discovered we
get better, faster ash values from the residue in the oxygen bomb
cup. The cup itself needed to be set on a hot plate for a few
minutes after it was carefully removed from the bomb so that the
contents were not spilled. It was also necessary to carefully
remove any ignition wire beads that landed in the cup. That said, it
was faster and easier than the muffle furnace technique. In addition we
confirmed that sulfur and chlorine combustion products do not remain in
the cup but instead condense in an aqueous phase on the lid, walls, and
bottom of the bomb.
Even with these “improvements” the time and
manpower required to
perform the determinations on truck after truck and tank after tank
caused us to start looking at some new technology– ion
(IC). Chemically suppressed ICs were available from Dionex but the
system at that time were expensive and cumbersome to use –
solution preps and multiple pumps. Wescam came out with an
electronically suppressed system that was much simpler to use and
maintain. Now we could use IC to determine in 15 minutes and with a
simple sample injection, chlorine, bromide, sulfur and even phosphorus
in the waste fuel. Nitrogen continued to be a problem but was
dropped from the specifications as it was determined that the primary
source of the NOx from cement kilns was thermal NOx and that fuel
nitrogen had little impact. We did want to add fluoride to
line-up but IC at that time had difficulty separating the fluoride peak
from the water dip. Even that was dealt with. By
eluent in the bomb and using IC eluent for the bomb wash and any
subsequent diluting we eliminated the water dip. Adding
to our test regimen greatly aided in future AFR development.
Technical creativity, supportive management at Systech, and critical
QA/QC follow up allowed us to develop 26 years ago many of the methods
that are still used today to test for alternative fuels and raw
materials for cement kilns and make the sustainable development
programs of today possible.
contact David Gossman at 847-683-4188 or
by e-mail at firstname.lastname@example.org
for additional information – or if you have memories to share.